Electrical-circuit protector.



No. 800,826. PATENTED OCT. 8, 1905.

. C. A. ROLPB. ELECTRICAL CIRCUIT PROTECTOR.

APPLICATION FILED FEB.13. 1903.

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UNITED STATES PATENT oFFIcE.

CHARLES A. ROLFE, OF ADRIAN, MICHIGAN, ASSIG'NOR, BY MESNE ASSIGNMENTS, TO ROLFE ELECTRIC (10., OF ROCHESTER, NEW YORK, A CORPORATION OF NElV YORK.

ELECTHlCAL-ClRCUlT PROTECTOR.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filed February 13, 1903. Serial No. 148,228.

T wZZ whont it nan/y concern:

Be it known that I, OHARLns A. ROLFE, a citizen of the United States, residing at Adrian, in the county of Lenawee and State of Michigan, have invented a certain new and useful Improvementin Electrical-CircuitProtectors, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to electrical-circuit protectors for protecting electrical circuits and instruments from unduly-strong currents.

The object of my present invention is to provide a simple, practical, and effective form of protective device and to arrange for the automatic shunting of the circuit upon the intrusion thereon of an unduly-strong current.

In the accompanying drawings, Figure 1 is an elevation of an electrical-circuit protector embodying my present invention. Fig. 2 is a plan view of the same with the glass cover removed. Fig. 3 is a section taken on line 3 3 in Fig. 2, with the glass cover in place, however. Figs. 4 and 5 are respectively side and end views of a heat-cartridge involved in the construction of the device.

In the device which I have shown to carry out my present invention a base 1 of insulating materialsuch as porcelain, slate, rubber, or the likeis provided and is equipped with a glass dome 2, which is held in position by a thumb-nut 3 at the top of a post A, which is secured to and rises from the base 1. The instrument is intended to protect both sides of a single circuit and to such end is provided with two separate protective devices, one for each side of the circuit. In the instrument shown these protective devices are the same in construction, and therefore a description of one will be suflicient.

Each device consists of a pair of spring strips or posts 5 and 6, which are secured to the base 1 by screws 7 and 8, respectively, and rise from the base. These springs 5 and 6 tend to spring away from one another. Mounted at the top of these springs and supported thereby is a device A, which is commonly called a heat-cartridge,which is mounted at the tops of the springs, so as to be readily removable therefrom. This cartridge A consists of a body 9 of insulating ma terial, provided at its opposite ends with caps 10 and 11. The cap 10 is provided with a groove 12, Fig. 4t, thereby forming a head 13, adapted to engage the spring 6. The cap 11 extends outwardly and is bifurcated to form two ears 14 14L, and between these is located a small bell-crank lever 15, which is pivoted upon a pin 16. The upper end of the lever 15 extends outwardly in a rearward direction from the ears let 14:, and the lower end of the lever extends down below said ears. A pin 17 extends across the outer ends of the cars 141 14. A small quantity of solder 18 is placed between the ears 14 14, so as to hold the lever 15 rigidly in position when the solder is hard. The ears 14: 14 are provided with apertures 18 18, by which this solder can be placed upon the lever 15. The end of the body 9 of insulation is transversely bored, and a stick or pencil 19 of graphite is arranged in such bore. The upper end of the graphite stick 19 comes in contact with the cap 11 at 20, and the lower end of the graphite projects below the lower side of said cap. A spring 21 is secured bya small screw 22 to the cap 10 and extends lengthwise of the cartridge to and below the lower end of the graphite stick 19, with which it makes contact. The graphite stick 19 is desirably electroplated at each end, so as to make good contact with the cap 11 and spring 21. A spring 23 is secured by a screw 2 k to the body of insulation 9 and is extended over the cap 11 to the upper end or arm of the bell-crank lever 15, upon which it presses. In the rear of the spring 5 is a contact strip or post 25, which is secured to the base 1 by a screw 26. The springs 5 5 are connected with the line-wires 27 27 of the circuit, and the springs 6 6 are connected with the instrument-wires 28 28. The springs 25 are connected with a ground-wire 29.

To place the instrument in normal condition, the cartridges A A are mounted upon the springs 5 5 and 6 6, which latter are forked slightly at their upper ends for that purpose. The caps 10 1O engage with the springs 6 6, and the lower ends of the levers 15 15 engage with the springs 5 5. The springs 5 and 6 are thus held under tension, as shown in full lines in Fig. 3. So long as the current in the circuit is normal these springs are held in tension and the circuit is closed through the one cartridge only is heated suliiciently to soften the solder of that cartridge, the lever 15 thereof will be swung outwardly by the spring 5 engaging the same, thereby permitting said spring 5 to spring outwardly and engage the spring or contact 25 in its rear,

the pin 17 engaging the spring 5 to prevent its entire separation from the cartridge. By the spring 5 making contact with the contact 25 the line side of the circuit is grounded, thereby shunting the unduly-strong current to ground. If the graphites of both cartridges become suflicientl y heated to soften the solder, the releasing of the levers 15 15 permits both springs 5 5 to swing outwardly, thereby coming into contact with the ground-contacts 25 25 and grounding the line as before. Upon the operation of either cartridge the spring 5 associated therewith becomes disengaged from its lever 15 by the swinging or pivotal motion of such lever, and immediately thereafter the spring 23 acts upon such lever 15, restoring it at once to its original or operative position. This takes place while the solder is still soft, so as to permit the free movement of the lever 15, and after such restorative movement the solder hardens and again holds the lever 15 securely in position. When an attendant examines the circuit and locates the trouble, the cartridge or cartridges, according as one or both of them have operated, are found in operative condition, so that the attendant can simply reengage the springs 5 5 with the levers 15 and set the device in condition for another operation.

It will be seen that the device is simple, practical, and effective and that it permits the line to be automatically shunted as opposed to opening the circuit, and that immediately after this occurs the heat-cartridge is restored to operative condition, so that the device can be again reset without either renewal of parts or repairs thereon.

What I claim as my invention is- 1. An electrical controller comprising thermally-operable means for automatically shunting the circuitand maintaining the same closed, and having provisions for automatically restoring itself to operative condition.

- 2. A solder-secured electrical controller, comprising means for shunting the circuit and maintaining the same closed, and having pro-- Visions for automatically resoldering itself in operative condition.

3. An electrical circuit-protector, comprising thermally-operable means for shunting the circuit on the passage of an unduly-strong current and maintaining said circuit closed,

and having provisions for automatically restoring itself to operative condition preparatory for a subsequent operation.

at. A solder-secured electrical-circuit pr0- teeter, comprisingmeans releasable on the passage of an n nduly-stron g current, for shunting the circuit and maintaining the same closed, and having provisions for automatically resoldering itself in operative condition.

5. A solder-secured electrical-circuit proteeter, comprising securingmeans releasable on the passage of an mainly-strong current, for grounding the circuit andmaintaining the same closed, and having provisions whereby it is automatically reset preparatory for another operation, and resoldercd in reset condition.

6. In a device of the class specilied, the combination of a spring-arm, a heat-cartridge holding the same normally in restraint but adapted to release the same upon the passage of an unduly-strong current, and a stop on said cartridge to make contact with the springarm, and prevent opening the circuit, substantially as described.

7. 1n adevice of the classspecilied, thecombination of a spring, a contact with which said spring tends normally to make connection, a heat-cartridge holding said spring normally in restraint, said cartridge being adapted to operate to release the spring upon thepassage of an excess current, said cartridge being provided with a stop or abutment adapted to engage said spring after operation and prevent opening of the circuit, substantially as described.

S. In adevice of the classspecilied, the combination of a contact, aspring tending to make connection with said contact, a heat-cartridge holding said spring normally in position, said cartridge being provided with a heat-concentrating device, a small quantity of solder, an arm held normally in position by said solder, and a stop adapted to engage the spring when the same is released by the softening of the solder, said stop being connected with the circuit, whereby it prevents opening thereof when the device operates, substantially as described.

9. In a device of the class specified, the combination of a contact, a spring tending to make connection with said contact, a heat-cartridge holding said syn'ingnorlnally in position, said cartridge being provided with a heat-concentrating device, a small quantity of solder, an arm held normally in position by said solder, means for automatically restoring said arm to normal position after operation, and a stop adapted to engage the spring when the same is released by the softening of the solder, said stop being connected with the circuit, whereby it prevents opening thereof when the device operates, substantially as described.

10. In an electrical-circuit protector, asolder-seeured heat-cartridge having provisions against movement by solder, and having provisions for automatically resoldering itself in operative condition, and also provided with a 5 stop at one side of said abutment, whereby the spring, after release by the abutment, engages the stop.

In witness whereof I hereunto subscribe my name this 22d day of January, A. D. 1903. CHARLES A. ROLFE.

\Vitnesses:

A. MILLER BELFIELD, I. C. LEE. 

